We have a Houston Instruments DMP-50 pen plotter recently donated, which is an old roll or sheet pen plotter than takes up to 36 inch wide paper. Serial port, I think.

I think we could find a vinyl cutter swivel knife holder that would fit this, or the plotter or the knife holder modded to fit. This could be great for printing out full size templates, blueprint style plans, and for cutting out sign vinyl to make our own sighs and banners. Aftermarket vinyl cutter blade holders are on eBay for very cheap prices now, under $20 will get a holder with a lot of extra blades.

Roland seems to be the most widely available, then second is Graphtec.

Then there is the issue of swivel offset compensation. Without swivel compensation, corners will be rounded and ends of cuts won't quite meet up. Please do not confuse this with cutter offset in CNC and G-code, which is a fixed outer or inner offset. With a swivel knife, the blade must drag slightly behind the centerline so that it will swivel to line up with the direction of travel. That means if you simply move the cutter in a square, the corners will be rounded off. So the centerline must go past the corner point by the offset of the tip, then smoothly move back into line with the direction of travel after the corner.

The old Graphtec I have (had, it doesn't work any more) uses a small triangle in a square to test offset cut compensation. Corners should be sharp and weed cleanly.

Some cutters have compensation in firmware, some in the driver, some rely on commercial sign cutting software to accomplish this. I think we can agree that free is good, open source and free is better. It looks like Inkscape has an extension called InkCut for offset cut compensation now, but it may only work with HPGL output for HP plotters.

Ok, so I actually have one of these units. There is software out there that can run this thing, it is built into inkscape and is found under the "plot" export functionality. The language these things talk in is DMPL, which is rs-232 based, the only problem is that the cable has a different pin out. The DMP 50 is one of the better candidates for conversation to a vinal cutter, the pen holder can have a larger spring installed to get the downforce required for vinal cutting, not something that most plotters can have happene. Unfortunately, my HI-50s eprom died before I could start cutting vinal with it, so now I have a HP-7586b 48" pen plotter, that unfortunately does not have enough down force to cut vinal.

If you want more info on the software to run the thing, check out https://www.timewasters-place.com/inksc ... s-the-2nd/ . This is the guy who wrote the plugin. Also, I can't find the website that has the proper pin out for the cable right now, but I did find it on the net last time, and I will check if I can find my manual, which has the pin out in it.

HPGL (Hewlett Packard Graphic Language) is kind of the standard for driving plotters. Since Inkscape can do swivel knife compensation and can output as HPGL, it would be great to have an Arduino with an HPGL interpreter just as GRBL is a G-Code interpreter.

Although it would be even better if Inkscape could also export as G-Code with the same extension that allows compensation.

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot post attachments in this forum